The present invention relates to a multi-chamber type processing apparatus for processing an object to be processed, such as semiconductor wafer.
The manufacturing process for semiconductor devices conventionally employs the so-called xe2x80x9cclusteredxe2x80x9d multi-chamber type processing apparatus that comprises, in view of improvement in its throughput and prevention of contamination of semiconductor devices, a vacuum transfer chamber (transfer chamber) at the center of the apparatus, a plurality of vacuum processing chambers (process chambers) around the transfer chamber, one or more load lock chambers and a vacuum preparation chamber for heating or cooling the objects to be processed. The apparatus further includes a plurality of load ports each capable of mounting a cassette thereon. The load ports are connected to the load lock chambers through a transfer chamber on the side of the atmosphere, constituting a load port site. In the multi-chamber type processing apparatus, there are included: a processing apparatus that has a xe2x80x9cbatchxe2x80x9d type load lock chamber for accommodating the cassette itself or a plurality of objects, for example, semiconductor wafers (simply referred xe2x80x9cwafersxe2x80x9d after) in the cassette; and another processing apparatus provided with a single-wafer load lock chamber for accommodating a single wafer therein. The former apparatus will be called xe2x80x9cbatch type processing apparatusxe2x80x9d hereinafter. Similarly, the latter apparatus will be called xe2x80x9csingle wafer processing apparatusxe2x80x9d hereinafter.
The processing order in the batch type processing apparatus will be described. After first mounting a sealed (closing) type cassette on the load port, a first transfer arm in the atmospheric transfer chamber conveys the cassette itself or all wafers in the cassette, for example, thirteen or twenty-five pieces of wafers, into the load lock chamber. Next, the load lock chamber is closed up and evacuated into vacuum. After the general equalization of pressure is established between the load lock chamber and the vacuum transfer chamber, these chambers are communicated with each other. Subsequently, each wafer in the load lock chamber is adjusted in position by an object positioning unit arranged in the vacuum transfer chamber or the vicinity and thereafter, a second transfer arm in the vacuum transfer chamber transports the aligned (positioned) wafer to a vacuum preliminary chamber or each vacuum processing chamber to apply a designated processing, such as thin film deposition, on the wafer. The processed wafer is again transferred to the load lock chamber or the cassette therein by the second transfer arm. Upon collecting all the wafers, the load lock chamber is sealed up again to raise the pressure of the atmosphere in the chamber. Next, the load lock chamber is communicated with the transfer chamber on the side of the atmosphere. Thereafter, the first transfer arm either conveys the cassette to the load port or transports the wafer to the cassette on the load port.
While, the processing order of the single wafer processing apparatus is as follows. After the wafers in the cassette mounted on the load port have been adjusted in position by the object positioning unit in the vicinity of the transfer chamber on the side of the atmosphere, the first transfer arm transfers the wafers into the load lock chamber one by one. Next, the load lock chamber is sealed up and evacuated for vacuum. As similar to above, after the pressure of the atmosphere in the load lock chamber becomes equal to the pressure of the atmosphere in the vacuum transfer chamber substantially, the interior of the load lock chamber is communicated with the vacuum transfer chamber. Thereafter, the second transfer arm transports the wafer in the load lock chamber to the vacuum preliminary chamber or each vacuum processing chamber to apply a designated processing similar to the above on the wafer. The processed wafer is again transferred to the load lock chamber by the second transfer arm. After the load lock chamber is sealed up again to raise the pressure of the atmosphere in the chamber, the load lock chamber is communicated with the transfer chamber on the side of the atmosphere. Thereafter, the first transfer arm transports the wafer to the cassette on the load port. Note, the above-mentioned steps are successively carried out every cassette.
In order to reduce the possibility that particles invade the interior of the transfer chamber on the side of the atmosphere, the batch type processing apparatus and the single wafer processing apparatus commonly supply the transfer chamber on the side of the atmosphere with a clean gas, such as N2, to make the pressure of the transfer chamber relatively higher than the pressure of a clean room having the transfer chamber on the side of the atmosphere, the load port site, etc. arranged therein.
In the above-mentioned batch type processing apparatus, however, it takes a lot of time to exhaust the atmosphere in the load lock chamber or supply the same chamber with gas since the load lock chamber is formed with a volume capable of accommodating a cassette itself or several wafers. Additionally, since the batch type processing apparatus has to arrange the object positioning unit adjacent to the vacuum transfer chamber, the number of wafer delivery times by the second transfer arm is increased to make the transfer time (cycle) long. Consequently, the problems may cause the throughput of the apparatus to be lowered.
In the above-mentioned single wafer processing apparatus, when the first transfer arm or the second transfer arm is constructed to carry the only wafer, it takes a lot of time to deliver the wafer through the load lock chamber. If a plurality of mount tables for mounting the wafer thereon is provided in the load lock chamber, then it is possible to reduce the above wafer delivery time. However, as similar to the batch type processing apparatus, it takes a lot of time to exhaust the atmosphere in the load lock chamber or supply the same chamber with gas because the volume of the load lock chamber is increased. Consequently, the problem may cause the throughput of the apparatus to be lowered.
Under such a situation, the present invention is provided in consideration of the above-mentioned problems in the conventional art. The object of the invention is to provide a new and improved multi-chamber type processing apparatus which is capable of substantially shortening a time until an object in the cassette has been loaded into the vacuum processing chamber, a transportation cycle of the object in the second transfer chamber and a time until the processed object has been loaded into the caste, thereby to improve the throughput of the apparatus.
In order to accomplish the above object, the present invention provides a processing apparatus, which includes: a first enclosure defining a first transfer space having an atmosphere of atmospheric pressure; a load port site, in which a plurality of load ports are aligned adjacently to the first transfer space, each of the load ports being capable of mounting a cassette for accommodating objects to be processed, the cassette having a door; a plurality of door openers provided at the load ports respectively to open and close the door of the cassette, the door openers each allowing the first transfer space to communicate with an interior of the cassette when the door opener opens the door of the cassette; a second enclosure defining a second transfer space having an atmosphere of vacuum or negative pressure; a plurality of vacuum processing chambers arranged around the second transfer space; a plurality of load lock chambers opposed to the load port site over the first transfer space and also disposed between the first transfer space and the second transfer space, the load lock chambers each capable of accommodating only one object therein; first gate valves arranged at the load lock chambers, respectively, to separate the load lock chamber from the first transfer space; second gate valves arranged at the load lock chambers, respectively, to separate the load lock chamber from the second transfer space; third gate valves arranged at the vacuum processing chambers, respectively, to separate the vacuum processing chamber from the second transfer space; a positioning unit that adjusts the positions of an object and is arranged adjacent to the first transfer space; a first transfer unit arranged in the first transfer space to transfer an object among the cassette, the load lock chambers and the positioning unit, the first transfer unit having two holders each capable of holding only one object; and a second transfer unit arranged in the second transfer space to transfer the objects between the load lock chambers and the vacuum processing chambers, the second transfer unit having two holders each capable of holding only one object.
With the constitution mentioned above, owing to the adoption of the single substrate processing apparatus capable of accommodating the only one object in each load lock chamber, it is possible to reduce the volume of each load lock chamber in comparison with that of a xe2x80x9cbatchxe2x80x9d type load lock chamber, whereby both evacuation (vacuum formation) time and gas-supply time of the load lock chambers can be shortened substantially. Additionally, with the adoption of the above load lock chambers, it is possible to reduce the number of delivering the object by the second transfer unit arranged in the second transfer space having a pressure reduced atmosphere since the positioning unit is arranged adjacent to the first transfer unit. Each of the first and second transfer units is capable of carrying two objects to be processed and also transporting each object in a predetermined direction. Therefore, even when adopting the load lock chambers each capable of accommodating the single object, it is possible to accomplish prompt delivery/replacement of the object between the first transfer space and each load lock chamber and also between the load lock chamber and the second transfer space. Consequently, with the shortening of respective transportation time and gas-supply/exhaust time, the throughput of the apparatus can be improved. Furthermore, since the load lock chambers are arranged to oppose the load port site over the first transfer space, the transportation distance for the objects can be reduced to shorten the transportation time.
In the present invention, preferably, the first transfer unit is movable in a direction parallel with an arrangement direction of the load ports and the positioning unit is adjacent to an end of the first transfer space with respect to the arrangement direction of the load ports. If a linear motor drives to move the first transfer unit in parallel with the arrangement of the load ports, then it is possible to transfer the object promptly. Further, owing to the above arrangement of the positioning unit adjacent to the end of the first transfer space in the arrangement direction of the load ports, there is no limitation to arrange the respective load ports and the respective load lock chambers.
Further, the positioning unit may be arranged between two of the load lock chambers. Then, since it is possible to reduce the transportation distances of the object between the respective load ports and the positioning unit and also between the positioning unit and the respective load lock chambers relatively, the transportation period of the object can be shortened to improve the throughput of the apparatus furthermore.
Further, if the load lock chamber is provided with a cooling unit for cooling the objects or a heating unit for heating the objects, then there in no need to provide a cooling chamber or a heating chamber in the neighborhood of the second transfer space. As a result, since the steps of transporting the object to the cooling chamber or the heating chamber can be eliminated, it is possible to reduce the number of transporting the object by the second transfer unit, improving the throughput of the apparatus furthermore.
Further, if circulating the clean gas in the first transfer space, it is possible to prevent particles from invading the first transfer space, the load lock chambers and the opened cassette and also possible to prevent the particles from adhering to the objects, thereby improving the yield of products.